• Title/Summary/Keyword: key-agreement

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Heat Transfer Measurement Using a Transient Liquid Crystal Technique and Numerical Anlysis (과도액정기법을 이용한 열전달 측정 및 수치해석)

  • Hong Cheol-Hyun;Lee Ki-Baik;Yang Jang-Sik
    • Journal of Advanced Marine Engineering and Technology
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    • v.29 no.1
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    • pp.68-77
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    • 2005
  • A transient liquid crystal technique has become one of the most effective ways in measuring the local heat transfer coefficients on the entire surface. The key Point of this technique is to convert the inlet flow temperature into an exponential temperature profile using a mesh heater. In order to verify the validity of this technique. the heat transfer characteristics on the wall surface by a pair of longitudinal vortices is investigated experimently and numerically. A standard ${\kappa}-{\varepsilon}$ is used for the numerical analysis of turbulent flow field. It is found from experiment and numerical analysis that two peak values exist over the whole domain. as the longitudinal vortices move to the farther downstream. these peak values decrease and the dimensionless averaged Nusselt number with the lapse of time is maintained nearly at constant values. The experiment results obtained from the present experiment in terms of the transient liquid crystal technique are in good agreement with the numerical results. Therefore, the transient liquid crystal technique developed for the measurement of heat transfer coefficient is proved to be a valid method.

Characteristics of Nursing and Caring Concepts Measured in Nursing Competencies or Caring Behaviors Tools (간호 역량 또는 돌봄 행위 측정도구를 통해서 살펴본 간호와 돌봄의 특성)

  • Park, Eun-Jun;Kim, Myung-Hae
    • Journal of Korean Academy of Nursing Administration
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    • v.22 no.5
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    • pp.480-495
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    • 2016
  • Purpose: The purpose of the study was to identify characteristics of nursing and caring concepts measured by nursing competencies or caring behaviors tools for general nurses working in acute care hospitals. Methods: Five major nursing literature databases were used to identify the relevant tools. The study included 19 nursing competencies tools with a total of 843 measurement items and 12 caring behaviors tools with 334 items. According to the International Council of Nurses (ICN)'s Competencies Framework and 8Cs suggested by Roach (1987) and Pusari (1998), the measurement items were classified by two researchers independently first and in agreement finally. Results: Competency of 'key principles of care' including sub-areas of the ICN Framework was most commonly found: on average 49.3% of nursing competencies items and 91.9% of caring behaviors items. 97.0% of the caring behaviors items were classified into one of six Cs: competence (27.5%), confidence (21.3%), compassion (17.1%), commitment (16.5%), communication (9.9%), or conscience (4.8%). Conclusion: Nursing competencies tools were more likely to measure 'what to do' focusing on tasks, while caring behaviors tools were to measure 'how to do' focusing on nurses' attitudes or values. Nursing practices should be evaluated with both nursing competencies and caring behaviors tools, considering that nursing and caring were differently conceptualized in the quantitative tools.

Test Results and Nonlinear Analysis of RC T-beams Strengthened by Bonded Steel Plates

  • Ren, Wei;Sneed, Lesley H.;Gai, Yiting;Kang, Xin
    • International Journal of Concrete Structures and Materials
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    • v.9 no.2
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    • pp.133-143
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    • 2015
  • This paper describes the test results and nonlinear analysis of reinforced concrete T-beams strengthened by bonded steel plates under increasing static loading conditions. The first part of this paper discusses the flexural tests on five T-beams, including the test model design (based on similarity principles), test programs, and test procedure. The second part discusses the nonlinear numerical analysis of the strengthened beams, in which a concrete damage plasticity model and a cohesive behavior were adopted. The numerical analysis results are compared with experimental data and show good agreement. The area of bonded steel plate and the anchor bolt spacing were found to have an impact on the cracking load, yield load, and ultimate load. An increase in the area of steel plate and a reduction of the anchor spacing could significantly improve the cracking and ultimate loads and decrease the damage of the beam.

Lightweight Self-consolidating Concrete with Expanded Shale Aggregates: Modelling and Optimization

  • Lotfy, Abdurrahmaan;Hossain, Khandaker M.A.;Lachemi, Mohamed
    • International Journal of Concrete Structures and Materials
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    • v.9 no.2
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    • pp.185-206
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    • 2015
  • This paper presents statistical models developed to study the influence of key mix design parameters on the properties of lightweight self-consolidating concrete (LWSCC) with expanded shale (ESH) aggregates. Twenty LWSCC mixtures are designed and tested, where responses (properties) are evaluated to analyze influence of mix design parameters and develop the models. Such responses included slump flow diameter, V-funnel flow time, J-ring flow diameter, J-ring height difference, L-box ratio, filling capacity, sieve segregation, unit weight and compressive strength. The developed models are valid for mixes with 0.30-0.40 water-to-binder ratio, high range water reducing admixture of 0.3-1.2 % (by total content of binder) and total binder content of $410-550kg/m^3$. The models are able to identify the influential mix design parameters and their interactions which can be useful to reduce the test protocol needed for proportioning of LWSCCs. Three industrial class ESH-LWSCC mixtures are developed using statistical models and their performance is validated through test results with good agreement. The developed ESH-LWSCC mixtures are able to satisfy the European EFNARC criteria for self-consolidating concrete.

A Study of Security Checks for Android Least Privilege - focusing on mobile financial services - (모바일 앱 최소권한 사전검증에 관한 연구 - 금융, 안드로이드 운영체제 중심으로 -)

  • Cho, Byung-chul;Choi, Jin-young
    • Journal of Internet Computing and Services
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    • v.17 no.1
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    • pp.91-99
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    • 2016
  • A security system in Android OS adopts sandbox and an permission model. In particular, the permission model operates the confirmation of installation time and all-or-nothing policy. Accordingly, the Android OS requires a user agreement for permission when installing an application, however there is very low level of user awareness for the permission. In this paper, the current status of permission requirement within mobile apps will be discovered, and the key inspection list with an appropriate method, when a mobile service provider autonomously inspects the violation of least privilege around financial companies, and its usefulness will be explored.

Forces Prediction by Indirect Force Measurement and Pseudo-inverse Technique (간접 힘 측정 방법과 가상 역행렬을 이용한 힘 예측)

  • Ahn, Byoung-Ha;Shim, Jae-Sool
    • Journal of the Korean Society for Precision Engineering
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    • v.19 no.6
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    • pp.43-50
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    • 2002
  • In the design of structure, the forces acting on tai structure are key parameter fur noise and vibration control. However, in the complex structure, the forces at the injection point on the structure cannot be measured directly. So, it is necessary to find out Indirect force evaluation method. In this paper, forces have been measured with In-situ vibration responses and system information. And, three existing techniques of indirect force measurement, vita. direct inverse. principal component analysis and regularization have been compared. This paper shows that multi-vibration responses are essential for talc precise estimation of the forces. To check these conditions, rotary compressor is adopted as test sample, because it is very difficult to measure the injection forces from internal excitation to shell. It alas also been obtained that relatively higher force is transmitted through three welding paths to the compressor shell. It shows a good agreement between direct and indirect force evaluation with curvature shell and plate.

Workers' Experiences in Shift Work (근로자들의 교대근무 경험)

  • Kim, Young-Hea;Kim, Young-Mi;Koo, Mi-Jee;Kim, So-Hee;Lee, Nea-Young;Chang, Koung-Oh
    • Research in Community and Public Health Nursing
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    • v.18 no.2
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    • pp.284-292
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    • 2007
  • Purpose: The purpose of this study is to explore and understanding the nature of the shift workers' experience in industries requiring 24 hours-a-day service provision and support. For the Purpose, the present researcher made a research Question, "What are workers' experience in the shift work?" Methods: In the study, 5 male shift workers, 3 female shift worker and a woman (key informant) whose husband is a shift worker participated. Then profound interviews with the participants were made after their agreement. Results: The researcher classified the significant statements under 6 theme clusters, 1) sense of difference; 2) worries about health; 3) draining of emotion; 4) anxiety; 5) sadness; and 6) being comfortable. Conclusions: Shift work which is inevitable in modern society may have severe influences on shift workers' physical, mental and psychological aspects by causing their work cycle rhythm to be unbalanced. Finally, the researcher hopes that the results of the study would help understand workers' life and increase social concern and support to the workers.

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A Plan to Secure the International Currency on Korean Professional Engineer (기술사 자격의 국제적 통용성 확보 방안)

  • 조정윤
    • Journal of the Korean Professional Engineers Association
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    • v.32 no.3
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    • pp.92-105
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    • 1999
  • With the advent of the information age and the knowledge-based society, human resource development has become a key factor in determining a nation's competitiveness. And technological qualification systems have a direct and significant influence on human resource development. In order to guarantee Korea's continued development as a competitive member of the international community, it is demanded that a Korean Technology Qualification System (KTQS) is to accept international qualification criteria. This study was conducted in order to analysis current movements about the international mutual recognition of Professional Engineer and present problems for introducing APEC Engineer System to KTQS, and also recommend reasonable plans which overcome those. Under the WTO/GATS, the liberalization of trade in professional services will steadily increase. APEC activities to facilitate the portability of qualifications is considered complementary to the WTO movement. If the government attempts to introduce the APEC criteria for university degree requirements, university curriculum standards, programs for continuing professional developments(CPD), and practical, on-site experience. In the standpoints with the recent developments of APEC Engineer agreement on profession qualification, it is important to guarantee that Korean qualifications have a common, international currency. Measures have to be taken to harmonize the qualifications standards for Professional Engineer with those set out by the WTO/GATS movement. Also this will require an increase in the quality of university curriculum and an establishment of CPD. This process will be further enhanced by the organization of APEC Engineer Monitoring committee, Consisting of government officials, professional engineers and university professors. At this committee we can discuss the best strategies to keep our nation's interests.

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Impact Bending Test Simulations of FH32 High-strength Steel for Arctic Marine Structures

  • Choung, Joonmo;Han, Donghwa;Noh, Myung-Hyun;Lee, Jae-Yik;Shim, Sanghoon
    • Journal of Advanced Research in Ocean Engineering
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    • v.2 no.1
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    • pp.28-39
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    • 2016
  • This paper provides theoretical and experimental results to verify the crashworthiness of FH32 high-strength steel for arctic marine structures against ice impact. Assuming that side-shell structures of the Korean arctic research vessel, ARAON, with ice-notation PL10, collide with sheet ice, one-third-scale test specimens with a single transverse frame are manufactured. Impact-bending tests were conducted using a rigid steel striker that mimics sheet ice. Drop height was calculated by considering the speed at which sheet ice is rammed. Prior to impact-bending tests, tensile coupon tests were conducted at various temperatures. The impact-bending tests were carried out using test specimens fully fixed to the inside bottom frame of a cold chamber. The drop-weight velocity and test specimen deformation speed were measured using a high-speed camera and digital image correlation analysis (DICA). Numerical simulations were carried out under the same conditions as the impact-bending tests. The simulation results were in agreement with the test results, and strain rate was a key factor for the accuracy of numerical simulations.

Group Key Agreement Protocol Considering Computational Efficiency of Mobile Devices for Integrated Wired/Wireless Networks (무선 단말기의 계산 효율성을 고려한 유.무선 통합 네트워크 환경에 적합한 그룹 키 동의 프로토콜)

  • Chang Woo-Suk;Kim Hyun-Jue;Nam Jung-Hyun;Cho Seok-Hyang;Won Dong-Ho;Kim Seong-Joo
    • Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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    • 2006.06a
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    • pp.322-325
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    • 2006
  • 그룹 키 동의 프로토콜에 관한 연구는 그동안 많은 연구자들에 의해 다양한 관점에서 진행되어왔으며, 최근 Nam 등이 유 무선 통합 네트워크 환경에서 효율적이면서도 안전한 그룹 키 동의 프로토콜을 제안하였다. 유 무선 통합 네트워크 환경에 적합한 그룹 키 동의 프로토콜을 설계하기 위해서는 고성능 연산 능력을 가진 유선 단말기의 특성과 상대적으로 계산능력이 떨어지는 무선 단말기의 특성이 함께 고려되어야 한다. 특히, 시스템자원의 제한성을 갖는 무선 단말기에서의 계산량을 최소화하는 문제는 그룹 키 동의 프로토콜 설계에 있어서 무엇보다 중요하다. 따라서, 본 논문에서는 무선 단말기의 계산량을 최소화하면서 유 무선 통합 네트워크 환경에 적합한 효율적인 그룹 키 동의 프로토콜을 제안하고자 한다.

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